The present invention relates generally to the field of catheters for use in the removal and/or delivery of a fluid to a patient. More specifically, the present invention relates to a catheter having an improved fluid flow rate and reduced fluid pressure.
Various medical procedures require the use of a catheter for the removal and/or delivery of a fluid to a patient. One example is the excorporeal treatment of blood, e.g., hemodialysis. The use of a catheter for hemodialysis requires a first lumen that accommodates blood flow from the patient (arterial lumen) in order to treat the blood and thereby remove various toxins. A second lumen is required in order to return the treated blood to the patient (venous lumen).
One previous type of catheter included an aspiration port and an infusion port opening from the end of a single catheter. However, there are several disadvantages with this design. In particular, the placement of a single aspiration and infusion port at the end of a catheter is problematic because of the risk of occlusion. Catheter ports can become partially or totally occluded by a build-up of thrombused blood, fibrin sheathing and/or drug residuals. Moreover, thrombused blood in catheter lumens or ports has been shown to be a nidus for infection. Obviously, these problems drastically reduce the effectiveness of the treatment, increase patient risk and frequently require clinical intervention with a lysing agent to restore patency.
Another problem with all types of catheters that are used to aspirate blood from a vessel is the suction pressure at the aspiration port. The suction pressure required to aspirate blood frequently causes the aspiration port to be occluded by intimal tissues within the vein resulting in tissue damage and clotting.
One attempt to resolve the problems created by occlusion and improve flow rates requires the use of additional smaller ports in the catheter prior to the terminal end. Previously, these smaller ports have extended perpendicular to the fluid flow path so as to form a 90xc2x0 angle. While such smaller ports were intended to solve the problem of occlusion, they can cause other more severe problems. In particular, such previous catheters can increase the shearing of blood cells passing into and out of these smaller ports. The shearing of blood cells can result in problems such as the buildup of thrombused blood cells (clots) that can become dislodged and pass through the blood stream. Additionally, these smaller ports quickly become occluded due to the difficulty of flushing ports that are perpendicular to the fluid flow path. These occluded ports can serve as a nidus for bacterial colonization requiring antibiotic intervention and/or catheter removal and replacement.
Accordingly, there exists a need for a catheter with improved flow rates and reduced fluid pressure capable of overcoming the above-identified problems.
The present invention is directed to a catheter that improves flow rates without increasing fluid pressure, reduces turbulence around the ports, improves laminar flow around the outside of the catheter, and minimizes vessel trauma during use. A catheter embodying the present invention also reduces the possibility of occlusions and infections while minimizing the shearing effects on any fluid passing through the catheter.
The foregoing is realized in accordance with the present invention by providing an improved catheter for use in the withdrawal or delivery of a fluid to a patient. The catheter includes an elongate body having an outer and inner wall and an axial passageway extending the length thereof. The body has a proximal end, a terminal end and a primary port. A plurality of secondary ports are located adjacent the primary port. The secondary ports are spaced apart from the primary port and from each other. At least one of the secondary ports having a passageway that forms an angle greater than 20xc2x0 with respect to an axis of the axial passageway.
According to another aspect of the invention, a catheter system for use in the withdrawal and delivery of a fluid to a patient is provided. The system includes a first catheter and a second catheter. The first and second catheters each have an elongate body with an axial passageway extending the length thereof. The body of each catheter has a proximal end, a terminal end and a primary port. A plurality of secondary ports are spaced apart from the primary port and from each other. The secondary ports each include a radial passageway that forms an angle greater than 20xc2x0 with respect to an axis of said axial passageway.
According to another aspect of the invention, a catheter for use in at least one of the withdrawal and delivery of a fluid to a patient is provided. The catheter includes an elongate body having outer and inner walls and an axial passageway extending the length thereof. The body has a primary port, a proximal end and a terminal end. A plurality of secondary ports are spaced apart from the primary port and from each other. The axial passageway adjacent at least some of the secondary ports has a fluted shape.
According to yet another aspect of the invention, a kit for use with hemodialysis or the like is provided. The kit includes a first catheter having a first lumen for use with the aspiration of fluid from a patient. The kit also includes a second catheter having a second lumen for use with the delivery of a fluid to a patient. The lumen of the first catheter being substantially larger than the lumen of the second catheter.